Reproduction process by powder development and fixation of transferred image

ABSTRACT

A PROCESS FOR THE PRODUCING OF A NUMBER OF REPRODUCTIONS ON ORDINARY PAPER. THE REPRODUCTION PROCESS COMPRISES EXPOSING AN INTERMEDIATE SHEET COATED WITH A LIGHT-SENSITIVE OR HEAT SENSITIVE MATERIAL TO RADIATION TO FORM A METASTABLE LIQUID WHEN ITS MELT IS COOLED ON THE INTERMEDIATE SHEET IS AREAS CORRESPONDING TO THE LOCATION OF THE IMAGES ON THE ORGINAL SHEET, TRANSFERRING A PART OF THE IMAGE ONTO A RECEIVING SHEET, AND THEN SUBJECTING THE TRANSFERRED IMAGE TO POWDER DEVELOPMENT AND FIXATION.

United States Patent 3,694,203 REPRODUCTION PROCESS BY POWDER DE- VELOPMENT AND FlXATION OF TRANS- FERRED IMAGE K nji Okubo, 210 Nakanuma, Minami-Ashigara Machi, Ashigara-Kamigun, Kanagawa, Japan, and Toshihiko Nagai, deceased, late of Tokyo, Japan, by Kenichi Nagai, legal representative, -10, 4-chome, Yakumo, Megro-ku, Tokyo, Japan No Drawing. Original application Feb. 10, 1966, Ser. No. 529,909, now Patent No. 3,539,342. Divided and this application Apr. 2, 1970, Ser. No. 29,357

Claims priority, application Japan, Feb. 10, 1965, 40/7,155 Int. Cl. G03c 5/04 US. Cl. 96-27 3 Claims ABSTRACT OF THE DISCLOSURE A process for the producing of a number of reproductions on ordinary paper. The reproduction process comprises exposing an intermediate sheet coated with a light-sensitive or heat sensitive material to radiation to form a metastable liquid when its melt is cooled on the intermediate sheet in areas corresponding to the location of the images on the original sheet, transferring a part of the image onto a receiving sheet, and then subjecting the transferred image to powder development and fixation.

This is a division of application Ser. No. 529,909 filed Feb. 10, 1966, now Pat. No. 3,539,342.

This invention relates to a process for producing reproductions, and more particularly to a process for producing a number of reproductions on ordinary papers.

In accordance with the present invention, there is provided a reproduction process comprising exposing an intermediate sheet coated with a light sensitive or heat sensitive material to radiation, forming images of transferable material having a tendency to form a metastable liquid when its melt is cooled on the intermediate sheet in areas corresponding to the location of the images on the original sheet, transferring a part of the image of transferable material onto a receiving sheet, such as ordinary papers and films, and then subjecting the transferred image to powder development and fixation. The thus reproduced image is stable that discoloration and deterioration in quality, as is encountered on the ordinary reproducing materials of silver salt, does not occur. This is a first feature of this invention.

A second feature of this invention is that the transfer as mentioned above can be carried out many times, for example, ten, twenty, thirty or more times. That is, a number of productions can be obtained from one intermediate.

Any original can be used for this invention, if it is an original whose image portions have a selective absorption factor to infrared or ultraviolet rays. This is a third feature of this invention.

A fourth feature of this invention is that it is not necessary to incorporate any special chemicals in the receiving sheet, to provide any darkroom or use any liquid. That is, processing for producing reproductions is a dry system.

A fifth feature of this invention is to provide a cheap and simple reproduction process.

Other features and advantages will hereinafter appear.

(1) INTERMEDIATE SHEET NO. 1

An intermediate sheet of the present invention is prepared by applying a material capable of releasing at least a part of water of crystallization contained therein by heating on a support. The material having associated ice therewith water of crystallization is preferably one that can release the water of crystallization at a temperature range of from 40 C. to 200 C. As examples of such materials, there may be mentioned compounds such as sodium acetate trihydrate, tribasic sodium phosphate 12- hydrate, sodium sulfate 19-hydrate, lead acetate trihydrate, potassium alum 24-hydrate, ammonium alum 24- hydrate, ammonium ferrous sulfate 6-hydrate, and minerals such as clay and bentonite. These compounds and minerals may be applied to support, such as natural or synthetic resin films and paper, as an aqueous solution, suspension or dispersion, may be subjected to vapor deposition in vacuum, or may be rubbed into paper or a roughened surface of a support uniformly, after being finely divided.

In the preparation of the intermediate sheet of this invention, a natural or a synthetic resin may be used as a binder. For example, as a binder, there may be used an aqueous solution or suspension of gelatin, polyvinyl alcohol, polyvinyl pyrrolidine, or polyvinyl butyral. When a water-insoluble polymer is used as the binder, there is preferably employed a polymer which is water permeable, such polymer being used as a solution in a suitable organic solvent solution. For example, there can be used a benzene solution of a copolymer of methyl methacrylate-methacrylic acid, an ethyl alcohol solution of N- methoxymethyl-polyhexamethylene-adipamide or a henzene solution of ethyl cellulose.

In such a solution there is dispersed the material having water of crystallization associated therewith in the form of a fine powder, an aqueous concentrated solution or a suspension. The solution or suspension is applied to the support, which is then dried. When a suspension is used, a surface active agent is advantageously added in order to improve the suspension effect. Alternatively, the material having water of crystallization associated therewith may be applied to a support by vacuum deposition. In such a case, the water of crystallization may evaporate during the vacuum coating, but when the vacuum coated material is allowed to stand for several minutes or several ten minute periods in air, water vapor in the air is absorbed by the deposited compound or mineral as water of crystallization.

The coated surface of the thus prepared intermediate sheet is placed upon an original to be copied and is exposed to infrared rays. The printing then may be carried out by a transmission printing process, but a reflection printing process is preferred. In this case, exposure is from the side of the intermediate sheet, whereby fogs can be reduced and clear images can be obtained.

In order to make the reflection printing process easy, it is necessary to select a support for the intermediate sheet, which is transparent or translucent to infrared rays.

'Image portions of the original absorb infrared rays more than blank portions, and are heated thereby during the exposure to infrared rays. Hence, a part of the intermediate sheet, corresponding to the image portions, is heated and the crystals of the compound containing water of crystallization or minerals containing water of crystallization release their water of crystallization, which wets the surface of the intermediate sheet at these portions. When this intermediate sheet is developed with a powder developer having a composition described hereinafter, there is a different adhesivity of the powder developer between the portions where the water of crystallization is released and the portions where no such phenomenon occurs whereby the powder developer is attached more firmly to the former portion to give an image.

When the printing of an intermediate sheet is carried out by the reflection printing process as described above, the image of a powder developer becomes symmetrical to an original, that is, the so-called mirror image thereof. This is most desired in the present invention.

If the time of exposure to infrared rays is long, the crystals of the portions of the intermediate, corresponding to the image portions of the original, release first their water of crystalliation to wet portions of the intermediate, and, as the infrared ray exposure is further continued, the water is evaporated off, whereby the adhesive property to a powder developer is reduced. Meanwhile, the crystals of the intermediate in another part corresponding to the blank portions of the original release their water of crystallization by the long-period exposure to infrared rays, whereby the adhesivity to powder developer is increased. Therefore, a negative intermediate can be obtained from a positive original by a long-period exposure (negaworking).

The period of time between the infrared ray exposing operation and developing operation is preferably as short as possible. Development within, for example, seconds after infrared ray exposure may bring a good intermediate, but an elapse of 10 minutes or more after the exposure does not produce a good image having high contrast, due to the reduction of the difference in adhesivity of a powder developer. However, if the exposed intermediate is allowed to stand in air for 24 hours or more after exposure without development, the intermediate can be used again as an intermediate similarly to the other that has not been exposed to infrared rays. This is because the crystals from which the water of crystallization had been released again take up the moisture in the air by standing in air, and return again to the form of crystals containing water of crystallization.

(2) Intermediate Sheet No. 2

Another intermediate sheet of the present invention is prepared by applying a solution containing a light sensitive diazonium salt or a light sensitive azide compound on a support and drying the coated support. More particularly, on the same support as mentioned above there is applied as a subbing layer an aqueous solution of an isophthalic acid-triethylene glycol-ethylene glycol condensate, polyvinyl butyral, a maleic anhydride-vinyl acetate copolymer, or a mixed dispersion of gelatin and a resin or resins, or an aqueous solution of gelatin, followed by drying. A solution of a light sensitive diazonium salt or a light sensitive azide compound is applied to the resulting layer and dried.

In the case when it is possible to apply a solution of the diazonium salt or azide compound directly onto a support, the subbing coating may be reduced of course. In this case, a suitable coating agent may be added to the coating solution for improving the coating properties of the solution.

The light sensitive diazonium salts useful in the present invention include those generally used in conventional diazo papers such as the diazonium salts of p-phenylenediamine or derivatives thereof or p-aminodiphenylamine, the diazonium salts of p-monoalkylaniline, p,p'- tetrazodiphenyl or derivatives thereof, or double salts, sulfates, and fiuoroborates thereof, or those used for lithographic printing materials, for example high molecular weight compounds represented as follows:

The light sensitive azide compound of the present invention is preferably selected from those used for conventional diazo papers, for example, phenyl azide, naphthyl azide and the derivatives thereof.

As a solvent for the application of solution there is used water, in the case of the diazonium salt, and dimethylformamide in the case of the azide compound, in general. The solution of diazonium salt or azide compound may also contain gelatin or one or more synthetic resins such as those mentioned above.

The support surface side (back side) of the thus prepared intermediate sheet is placed upon a transparent or translucent original to be copied and exposed to a light of a wavelength to which the diazonium salt or the azide salt is sensitive through the original, for example, by the use of a mercury lamp by the transmission printing process from the back side of the original. Or, the coated surface side of the intermediate sheet is placed upon a transparent or translucent original turned over a transparent support, and then exposed to a mercury lamp by the transmission printing process from the surface side of the original.

When this intermediate sheet is developed with a powder developer having a composition described hereinafter, an image of the powder developer is given due to a difference of adhesivity of the powder developer to the exposed part and non-exposed part of the intermediate sheet. In this case also, the image of the powder developer is symmetrical or a mirror image to the original.

(3) Powder developer for developing an exposed intermediate A powder developer for developing the intermediate sheet as described in (1) and (2), after exposure, is made of a transferable material having a tendency to form a metastable liquid when its melt is cooled. The powder developer may be incorporated with an infrared rayabsorbing material in addition thereto. In this case, an image of the intermediate can be transferred to a receiving sheet by infrared heating.

There are various transferable materials, some of which are disclosed in detail in Belgian patent specifications No. 631,304 and No. 644,239. In the present invention, in particular, such transferable materials should be selected that are non-adhesive at room temperature, but become adhesive after becoming molten at a temperature in the range of from 70 C. to 170 C., and have a high supercooling property, that is to say are retained in a metastable liquid phase at room temperature for several minutes or several ten minute periods after becoming molten and cooled.

Typical examples of such transferable material are plasticizers, Santicizer 9 and Aroclor 1268, sold by Monsanto Chemical Company, benzotriazole, tribenzylamine, vanillin, phthalophenone, 2,4-dihydroxybenzophenone, benzyl, benzoin, sulfur, acetanilide, benzoic acid and phthalic anhydride, Santicizer 9 is a mixture of orthoand paratoluene sulfonamide melting at about C. The melt remains liquid when first cooled to or somewhat below room temperature. The material vaporizes at C. to produce a visible haze in a fog test as described in Stricklin U.S. Pat. 3,360,367 issued Dec. 26, 1967. This material provides a stable non-tacky thin coating on paper. Aroclor 1268 is a solid chlorinated diphenyl having a nominal specific gravity of 1.6461.653 and a vapor pressure of 760 mm. Hg at about 435 C.

As an infrared ray-absorbing material there is used a finely divided inorganic or organic pigment. Typical examples thereof are carbon black, iron oxides, chrome green, ultramarine blue, cobalt blue and indigo.

The powder developer for developing an exposed intermediate used in the present invention is prepared by the following procedure. One part by weight of a transferable material is thoroughly mixed with from 0 to 0.1

part by weight of a finely divided infrared ray-absorbing material and heated. When the transferable material is molten, the molten mixture is further blended sufficiently and cooled to normal temperature. The molten mixture, after being solidified completely is finely pulverized by suitable means and then granulated to a grain size of from about 0.1 to 100 microns in diameter. A mixture of a powder developer used in the conventional electrophotography (called toner) and finely divided transferable material may be used as the powder developer for developing an exposed intermediate of the present invention.

(4) Transfer of material from an intermediate sheet to a receiving sheet After the mirror image of an original formed on the intermediate sheet described in (1) or (2) by the powder developer described in (3), the intermediate sheet is heated by suitable means to raise the temperature to the melting point of the transferable material and then cooled to room temperature, whereby to fix the powder image of the original on the intermediate sheet. The coated side of the thus processed intermediate original sheet is placed upon a receiving sheet such as paper, film, glass, cloth and heated. The heating is carried out by holding them between two hot plates or by the use of infrared ray. Or, the surface of the intermediate is heated by infrared ray irradiation followed by placing thereon a receiving sheet, and pressing.

Then a part of the image portion of the intermediate sheet is transferred to a receiving sheet. In the case of employing the infrared ray heating, an infrared rayabsorbing material is preferably added to the transferable material.

The transferable material is thus transferred to a receiving sheet. The transferable material has supercooling properties and if the powder development is carried out just after the transfer, the powder developer is adhered only to that portion due to the adhesivity of the transferable material, whereby to form an image.

As the powder deevloper used for developing the receiving sheet there may be employed any fine powder having a suitable grain size to be adhered to a molten transferable material. Illustratively, the powder developers are generally prepared by dispersing in a thermoplastic resin, such as a phenol-formaldehyde resin, a molten mixture of chlorinated naphthalene and polystyrene or a copolymer of vinyl chloride and vinyl acetate, a carbonaceous material, such as carbon black or asphalt powder, an inorganic pigment, such as basic lead carbonate, zinc oxide, titanium dioxide, antimony trioxide, iron oxides, cadmium sulfide, basic chromate, molybdenum orange, cadmium yellow, chrome green, ultramarine blue, or an organic pigment such as benzidine yellow, indigo and alizarin, and granulating the thus prepared dispersion by a suitable method into granules having a diameter of from 0.1 to 50 microns. A toner used for conventional electrophotography is used in the present method. The color of such developers should be selected in accordance with the color of the receiving sheet.

Powder developer, the surface of which is treated with surfactant, which is described and claimed in our copending application No. 529,901 filed by Kinji Okubo et a1 (now US. Patent 3,431,412 granted March 4, 1969) can be used in the process of the present invention.

When the material is heated or treated with the vapor of an organic solvent, such as trichlene, (trichlorethylene), Freon, (dichlorodifiuoro-methane), acetone, chloroform and benzene, after the development, a visible printed image, which is not affected by light and moisture and can be stored permanently, can be obtained.

The transfer of a transferable material to a receiving sheet from one intermediate sheet can be carried out many times over, e.g., ten, twenty or more times.

The following examples further illustrate the present invention.

6 EXAMPLE 1 (1) Preparation of a powder developer for developing the intermediate sheet (a) Twenty grams of powdered Santicizer 9 and 1 g. of carbon black were blended, and heated at 110 C. to melt the blend. The molten mixture was stirred and blended in the molten state, cooled to room temperature and after solidification, granulated to a size of less than 74 microns in diameter.

(b) Twenty grams of powdered benzotriazole and 1 g. of carbon black were blended, and heated at about C. to melt the blend. The molten mixture was stirred and blended thoroughly in the molten state, cooled to room temperature and after solidification, granulated to a size of 74 microns or less in diameter.

(2) Five grams of gelatin were dissolved'in 200 ml. of Water. Five grams of sodium acetate trihydrate were dissolved, and 40 ml. of ethyl alcohol was added thereto with stirring. The stirring was continued for a further two minutes. (Ethyl alcohol plays a role of promoting a favorable growth of sodium acetate crystals and the drying thereof.) A mixture of 10 g. of zinc palmitate (to reduce fog) and 100 ml. of ethyl alcohol were treated in a ball mill for 24 hours to yield a dispersion, and 10 ml. of the resulting dispersion was added to the above mentioned solution. The resulting mixture, after stirring thoroughly, was applied to a cellulose triacetate film base to yield a coating having 60 mL/rn. and dried to give an intermediate sheet.

The coated side of the intermediate sheet was placed upon an original and subjected to a reflection printing process by exposing the back side of the intermediate sheet to infrared rays. The infrared exposure was conducted using a copying machine. After exposure, the intermediate sheet was developed with the powder developer described in (1)-(a). After powder development, the sheet was irradiated with infrared rays to heat and the image was fixed to give an intermediate image.

Then a receiving sheet was placed upon the image surface of the intermediate sheet, and heated by heater or by irradiating with infrared rays from the back of the intermediate sheet, whereby to melt a part of the transferable material and to transfer it to the receiving sheet. The receiving sheet was then subjected to powder development by the use of a toner followed by fixing in trichlene vapor. About thirty sheets of reproduction were obtained.

Example 2 Ten grams of gelatin were dissolved in 200 ml. of water. Ten grams of sodium acetate trihydrate were dissolved, and 20 ml. of ethyl alcohol was added thereto with stirring. The stirring was continued for two minutes more. A mixture of 10 g. of barium stearate and 100 ml. of ethyl alcohol were treated in a ball mill for 24 hours to yield a dispersion. After adding 30 ml. of the dispersion to the above mentioned solution with stirring, the resulting mixture was applied to a cellulose triacetate film base to yield a coating having 75 mL/rn. and dried to give an intermediate sheet. The intermediate sheet placed upon an original was exposed and developed in a similar manner as in Example 1. For development of the intermediate sheet there was used the powder developer described in (1)-(b) of Example 1. After powder development, the sheet was irradiated with infrared rays to heat and the image was fixed to give an intermediate image.

The transfer, development and fixation of the intermediate image were carried out in a manner similar to Example 1.

Example 3 Procedures similar to those described in Example 1 were carried out except that the intermediate sheet was prepared by pulverizing ammonium ferrous sulfate 6-hydrate and uniformly rubbing the powder, of a size passing through a 200 mesh sieve, into a tracing paper.

Example 4 A 4% ethyl alcohol solution of polyvinyl butyral was applied to a polyester film base and dried. A 2% aqueous solution of the condensation product of Formalin and the zinc chloride double salt of diazotized p-aminodiphenylamine was applied thereto to yield a coating having 70 mL/m. and dried to give an intermediate sheet. The support surface side of the thus prepared intermediate sheet was placed upon a transparent original to be copied and exposed to a mercury lamp by a transmission printing process from the back side of the original. Or, the coated surface side of the intermediate sheet was placed upon the transparent original turned over a transparent support, and then exposed to a mercury lamp by a transmission printing process from the surface side of the original. After the exposure, the powder development was carried out by the use of the powder developer described in (1)-(b) of Example 1. The sheet was then irradiated with infrared rays and the image was fixed to give an intermediate image.

The transfer of the intermediate image toa receiving sheet, the development and fixation were carried out in the similar manner to Example 1.

Example A 2% aqueous solution of sodium 2,1-diazonaphthol- 5-sulfonate was applied to a polyester film base to yield a coating having 30 ml./m. and dried to give an intermediate sheet.

The intermediate sheet, placed upon an original, was exposed and developed as in the Example 4. For the development of the intermediate sheet there was used the powder developer described in (1)-(a) of the Example l. After powder development, the sheet was irradiated with infrared rays and the image was fixed to give an intermediate image.

The transfer of the intermediate image to a receiving sheet, the development and the fixation were all carried out in a manner similar to that of Example 1.

What is claimed is:

1. A process for producing a reproduction of an original which comprises:

(1) superimposing a photosensitive material onto an original, said photosensitive material comprising a support coated with a compound selected from the group consisting of photosensitive diazonium salts and photosensitive azide compounds;

(2) exposing the photosensitive material through the original to light of a wavelength to which said photosensitive material is sensitive to form a latent image;

(3) developing said latent image by rubbing the surface of said photosensitive material with a transferable developer comprising a pulverized solid material which is hard and non-sticky at room temperature and which melts at temperatures of between to C., and having the further property of forming a metastable liquid when cooled below its melting point after having been heated to its melting point;

(4) transferring the developed image consisting of the hard and non-sticky transferable material onto a receiving sheet at a temperature suflicient to melt said developer to thereby form a metastable liquid;

(5) powder developing the transferred image consisting of said transferable developer in its molten state on said receiving sheet whereby said powder developer selectively adheres to said transferred image; and

(6) fixing the image consisting of the powder developer on said sheet.

2. The process of claim 1 wherein said photosensitive material is selected from the group consisting of the diazonium salt of p-phenylenediamine and derivatives thereof, p-aminodiphenylamine, p-monoalkylaniline, p,ptetrazodiphenyl or derivatives thereof, or double salts thereof, sulfates or fluoroborates thereof.

3. The process of claim 1 wherein said transferable material is selected from the group consisting of chlorinated diphenyl, benzotriazole, tribenzylamine, vanillin, phthalophenone, 2,4 dihydroxybenzophenone, benzyl, benzoin, sulfur, acetanilide, benzoic acid, phthalic anhydride, and a mixture of orthoand para-toluene sulfonamides.

References Cited UNITED STATES PATENTS 3,547,630 12/1970 Notley 9627 3,556,787 1/1971 Letter 9627 3,565,612 2/ 1971 Clark 9627 NORMAN G. TORCHIN, Primary Examiner E. C. KIMLIN, Assistant Examiner U .8. Cl. X.R. 9649 

